Encapsulação de carotenoides: um estudo do efeito na atividade antioxidante e anti-inflamatória no tecido adiposo

Abstract

Carotenoids act by reducing oxidative stress and, therefore, act on the inflammatory process. Encapsulation can preserve and/or enhance the functional properties of these natural pigments, such as antioxidant activity. In the present study, divided into chapters, we sought to evaluate how encapsulation acted to improve the antioxidant and anti-inflammatory activity of carotenoids. The first and second chapters, referring to the systematic review (SR), are organized as follows: the first presents the SR protocol with an international prospective registry of systematic reviews (PROSPERO, under number CRD42020142065); and the second, RS, which brought together and systematized studies in vitro, ex vivo, in vivo, which evaluated the effect of different carotenoid encapsulation techniques on antioxidant activity. The articles were selected according to the PICOS strategy (population, interventions, control, results and type of study) and searches were performed in PubMed, Embase, Virtual Health Library, Scopus, ScienceDirect and Web of Science databases. The methodological quality assessment was performed using the OHAT (Office of Health Assessment and Translation) tool. A total of 1577 articles were selected, resulting in 20 eligible studies. The results showed that encapsulation promoted changes in the chemical structure of carotenoids and the emergence of new chemical interactions, in addition to increasing the surface area, resulting in the preservation and enhancement of antioxidant activity. The third chapter refers to the experimental study, which evaluated the effect of the crude extract rich in carotenoids obtained from the Cantaloupe melon (Cucumis melo L. var cantalupensis) (EB) nanoencapsulated (EGS) in Wistar rats with inflammation induced by the consumption of high glycemic index and high glycemic load (HGLI) diet on systemic and adipose tissue inflammatory response. The EB was characterized by spectrophotometric and chromatographic methods, and the EGS was characterized by physical and chemical methods, as well as the evaluation of the incorporation efficiency. The in vivo experiment was carried out for 11 days with male Wistar rats (n = 20) with diet-induced inflammation, subdivided into four groups: no treatment (HGLI diet + water), conventional treatment (HGLI diet + nutritionally adequate diet), test 1 [HGLI and EB diet (12.5 mg/kg)] and test treatment 2 [HGLI and EGS (50 mg/kg)]. The groups were investigated in relation to food consumption, caloric intake, caloric efficiency and weight. Inflammatory cytokines were measured in plasma (TNF-α, IL-6 and leptin) and in adipose tissue (TNF-α and IL-6). In addition, the weights of visceral adipose tissue (retroperitoneal, epididymal and perirenal) were recorded, histopathological analyzes were performed, and investigation of the antioxidant activity in plasma and visceral adipose tissue through the quantification of malondialdehyde, sulfhydryls and superoxide dismutase (SOD) activity). For the in vivo experiment, no changes were observed in food consumption, intake, caloric efficiency and weight (p > 0.05). However, the animals treated with EGS had a lower mean variation in dietary intake and were the only group that showed only weight loss. This group also showed improvement (p < 0.05) in plasma concentrations of inflammatory cytokines (IL-6 and leptin), however, there was no difference in the dosage in adipose tissue. In visceral adipose tissue, it was found that the largest focal area of multilocular adipocytes was observed for the EGS-treated group. In addition, EGS may be acting in a mimetic way to SOD and, therefore, reducing oxidative stress. Thus, the present study presents a relevant scientific contribution, as RS generated information regarding the effect of nanoencapsulation on antioxidant activity and, in the preclinical study, on inflammation.